Formwork for concrete



Dec. 27, 1966 J. R. TOOLEY FORMWORK FOR CONCRETE 4 Sheets-Sheet 1 Filed Oct. 13, 1964 muml uuum Dec. 27, 1966 J. R. TOOLEY 3,294,357

FORMWORK FOR CONCRETE Filed Oct. 15, 1964 4 Sheets-Sheet 5 .lllllHlh Y .I HIIIHIII" Attorn yg Dec. 27, 1966 J. R. TOOLEY FORMWORK FOR CONCRETE 4 Sheets-Sheet 4 Filed Oct. 15, 1964 United States Patent 3,294,357 FQRMWORK FOR CONCRETE Jack Raymond Tooley, London, England, assignor to Acrow (Engineers) Limited, London, England Filed Oct. 13, 1964, Ser. No. 403,517

Claims priority, application Great Britain, Get. 16, 1963,

40,885/63 7 Claims. (Cl. 249-48) This invention relates to formwork for use in the construction of horizontal concrete slabs such as floors and which. will be referred to herein as slab formwork.

In the construction of such concrete slabs, it is usual for the forms to be in the form of rectangular panels supported from below so that they cannot be removed without depriving the slab cast on them of the whole of its support. As the slab may require some support while the concrete is maturing over a period which can be as long as 21 days, the panels cannot be struck and re-used for another part of the slab except when it is a question of a slab of enormous area, i.e. one which takes more than 21 days to cast.

The invention is concerned with enabling slab formwork to be used with the utmost economy and, more specifically, with constituting the formwork so that panel forms can be removed at an early stage without depriving the slab of the support given by other parts of the formwork.

This is achieved by constituting the formwork of a number of props, a number of beams supported directly by the props and a number of panels supported by the beams with their working faces level with the top surfaces of the beams so that they form a continuous casting surface therewith, through means which, in their working positions, are attached to the sides of the beams and are detachable therefrom to allow the panels to be struck without striking the beams.

With this system, the panels can be removed at an early stage after completion of the casting without removing the beams which, by themselves, provide sufiicient support for the slab during its maturing period.

The beams and the props are preferably provided with means such as interengaging pins and holes to ensure positive location of the beams. Also, the beams are preferably rolled steel I-section joists the Webs of which are provided with brackets for supporting the panel supporting means, the latter being preferably in the form of tubes provided with brackets which can be pivotally connected to the brackets on the beams so that when the panels are to be struck, the supporting tubes can be swung down while the panels are temporarily supported and be removed from the beams while they are out of contact with the panels.

An example of a slab formwork system in accordance with the invention is shown in the accompanying drawings, in which:

FIGURE 1 is a diagrammatic perspective view from above of the formwork in the working position;

FIGURE 2 is a perspective view from below on a larger scale of part of the formwork shown in FIGURE 1;

FIGURE 3 is a perspective view on an intermediate scale illustrating the use of the formwork; and

FIGURE 4 is a perspective view on a still larger scale of details of the formwork.

As will be seen from FIGURE 1, the formwork is made up of adjustable props arranged in rows, beams 12 supported directly by the props and forms 14 in the form of rectangular panels supported by the beams 12 through supporting members 16. The panels can be constructed in various ways. For use in accordance with the invention they will generally consist of a metal framework supporting a timber panel. As their manner of construction is of no importance in relation to the invention, they have Patented Dec. 27, I966 "ice been shown completely diagrammatically in the drawings.

The beams 12 are of the same length as the panels 14 and two end-to-end beams are supported by one and the same prop. The beams are positively located by the engagement of pins 18 (FIGURE 2) depending from the beams in holes in the cap plates 20 of the props or viceversa. They are in the form of I-section rolled steel joists.

The panels 14 are disposed in the spaces between the beams so that their top surfaces are level with the top surfaces of the beam and form therewith a continuous surface onto which a concrete slab can be cast. In normal practice, the panels rest on top of the beams, the latter not providing any of the casting surface. In that case, after the slab has been cast, the panels can be removed only with the beams or after the latter have been removed. With the construction shown here, the panels can be removed whenever desired while leaving the beams in the slab supporting position.

The members 16 which support the panels in their working positions are in the form of tubes of the same length as the panels and the beams. They are provided at intervals along their length with brackets 22 from which extend pins 24 having their axes parallel to that of the tubes. The webs of the beam are also provided with brackets 26 at the same spacing as the brackets 22 in which are formed holes 28 for receiving the pins 24.

When it is desired to support a panel in position, a supporting member 16 is pivotally connected to a beam 12 as shown on the left in FIGURE 4. The member 16 is then swung upwards into the position shown on the right in FIGURE 4. (The pins 24 are shown in FIGURE 4 to be engaged one from the right and one from the left. It is immaterial whether the engagement is left hand or right hand.) It is then locked in position by bolts 30 passing through holes 32 in the web of the beam and corresponding pairs of holes 34 in the tube. The same operation having been effected on the beam supported by the next row of props, a panel form can be lowered onto the two supporting members from above into the position shown in FIGURE 1.

When it is desired to strike or remove a panel, the latter is temporarily supported from below by means, for example, of adjustable props, the bolts 30 are removed and the supporting members are swung down into the position shown on the left in FIGURE 4. Thereupon, they can be removed by being moved axially to disengage the pins 24, this being possible without interference from the neighbouring supporting members. The formwork panel can then be lowered leaving the beams in position.

The supporting members 16 are in quite short lengths and are easily handled by one man. The placing in position and removal of the panels is, therefore, a simple and light task.

When a concrete slab has been cast, it rapidly reaches a state in which it requires relatively little support. It requires some support, however, for along time-maybe as long as 21 days. That support is more than adequately provided by the beams alone so that the invention allows the panels to be removed very shortly after the casting is completed and to be put to use elsewhere. The economy thus effected can be very substantial indeed. Thus, where it is a question of casting a slab of a superficial area of say 1,000 sq. yards, the contractor needs only about 45% of the number of forms he would require to complete the slab in the same time with forms which remained in position until completion of maturing of the concrete. In addition to the saving in capital cost, an important saving in transport and storage is effected.

In order to register the panels lengthwise of the supporting members, the latter can be provided at intervals with projecting lugs 36 engaging in corresponding grooves 38 in the panels.

The pins 24 on the supporting member brackets 22 and the holes 28 in the beam brackets 26 could, of course, be interchanged.

If required, the props can be braced as is customary.

I claim:

1. A system of slab formwork comprising a number of props, a number of beams supported directly by the props, a number of panels, and means pivotally mounted on the webs of the beams and supporting said panels in the working position with their casting faces level with the top surfaces of the beams and forming a continuous casting surface therewith, said means being swingable to a position in which the panels can be struck without striking the beams.

2. A system of slab formwork according to claim 1 in which the beams and the props are provided with interengaging means serving to locate the beams positively in their working position.

3. A system of slab formwork according to claim 2 in which the said means comprise interengaging pins and holes.

4. A system of slab formwork according to claim 1 which when a panel supporting means is pivotally swung downwards from the working position into an idle position the panel can be removed without interference from its neighbours.

5. A system of slab formwork according to claim 4 in which the beams are I-section joists, and the pivotally supporting means are brackets projecting from the webs of the joists and formed with holes to receive pins on the panel supporting means so that the latter can be swung into and out of their working positions about the axis of the pins and can be moved parallel to that axis for removal from the beams.

6. A system as claimed in claim 5 in which the pins are carried by the brackets on the joists which engage in holes in brackets on the panel supporting means.

7. A system of slab formwork comprising a plurality of props arranged in rows, a plurality of beams having flanges at their tops directly supported by said props to form a plurality of lines with a space between neighbouring lines, a plurality of rectangular forms disposed in said spaces and providing a continuous casting surface with said flanges, and means pivotally mounted on the webs of said beams having an elevated working position in which they project into the inter-beam spaces and support said forms and a lowered position, said form supporting means and their attachment means being slidable lengthwise of said beams for detachment therefrom when in their lowered position.

References Cited by the Examiner UNITED STATES PATENTS 6/1895 Burrage 25-l3l 4/1964 Bowden et al. 249-28 

1. A SYSTEM OF SLAB FORMWORK COMPRISING A NUMBER OF PROPS, A NUMBER OF BEAMS SUPPORTED DIRECTLY BY THE PROPS, A NUMBER OF PANELS, AND MEANS PIVOTALLY MOUNTED ON THE WEBS OF THE BEAMS AND SUPPORTING SAID PANELS IN THE WORKING POSITION WITH THEIR CASTING FACES LEVEL WITH THE TOP SURFACES OF THE BEAMS AND FORMING A CONTINUOUS CASTING SURFACE THEREWITH, SAID MEANS BEING SWINGABLE TO A POSITION IN WHICH THE PANELS CAN BE STRUCK WITHOUT STRIKING THE BEAMS. 